Variable curvature spherical bottom bus static deviation turning correction method

Abstract

The application provides a variable-curvature spherical-bottom generatrix static deviation turning correction method, which comprises the following steps: S1, dividing an arc surface box bottom into a plurality of generatrix surfaces along an axial direction, and uniformly arranging a plurality of measuring points on each generatrix surface in a circumferential direction; S2, offsetting an inner profile surface turning curve of a last turning state by a preset thickness to generate a current outer profile surface turning curve, and turning the outer profile surface according to the current outer profile surface turning curve; S3, counting the measuring points with the minimum thickness on each generatrix surface; S4, constructing a current inner profile surface turning curve according to the minimum thickness and the position of the measuring points; and S5, repeating S2-S4 until the turning is stopped when the minimum thickness reaches a thickness threshold. The application has the beneficial effects that the generatrix deviation after each turning is measured and corrected, the generatrix static deviation can be eliminated, the generatrix deviation before and after variable-curvature spherical-top bottom machining is reduced, the variable-curvature spherical-bottom constant-wall-thickness turning precision is improved, and the weight of the arc surface box bottom is reduced under the premise of ensuring the structural strength.

Description

Technical Field

[0001] This invention belongs to the field of turning technology, and in particular relates to a method for correcting static deviations in turning a variable curvature spherical base generatrix. Background Technology

[0002] The curved bottom is a crucial component of launch vehicles. Integral molded bottoms are characterized by short manufacturing cycles and high reliability, making them the future direction for bottom processing. Integral bottoms require large-area thinning after the forming process. Due to their characteristic of rotating with equal thickness, turning is the preferred process for mechanical thinning. Existing turning schemes all adopt a process of first turning the inner shape as the reference surface and then turning the outer shape to ensure equal thickness requirements. The deformation problem of the inner reference surface seriously restricts the accuracy of equal wall thickness turning.

[0003] Existing machining capabilities are insufficient for controlling wall thickness precisely when machining large-diameter products with small wall thicknesses. This becomes increasingly pronounced as the diameter increases and the wall thickness decreases. Due to the excessively high wall thickness control precision, and considering that the wall thickness of the product affects the overall load-bearing capacity of the launch vehicle's bottom, existing machining methods often employ a "thin-point-to-thickness" machining strategy. This results in a large area of ​​the overall bottom being excessively thick, which greatly increases the self-weight of the launch vehicle's bottom and further affects the launch vehicle's launch payload capacity. Therefore, improving the accuracy of wall thickness control during machining of the overall bottom is a critical issue that urgently needs to be addressed. Summary of the Invention

[0004] In view of this, the present invention aims to propose a method for correcting static deviations in the machining of variable curvature spherical bottom generatrices, in order to solve at least one of the aforementioned technical problems.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] The first aspect of this invention provides a method for correcting static deviations during machining of a variable curvature spherical base generatrix, comprising the following steps:

[0007] S1. Divide the bottom of the arc-shaped box into multiple generatric surfaces along the axial direction, and evenly set multiple measurement points around the circumference of each generatric surface;

[0008] S2. Based on the inner surface rotation curve of the previous turning state, perform equal thickness offset with a preset thickness to generate the current outer surface rotation curve, and perform turning of the outer surface using the current outer surface rotation curve.

[0009] S3. Collect the thickness at each measurement point and count the measurement points with the minimum thickness on each busbar surface;

[0010] S4. Construct the rotation curve of the current inner surface based on the minimum thickness on each generatrix surface and the position of the measurement point;

[0011] S5. Repeat S2-S4 until the minimum thickness reaches the thickness threshold and then stop turning.

[0012] Furthermore, in S1, U i There are a total of 16 circumferentially divided measurement points, V j The 16 busbar surfaces are divided into 16 sections with equal arc lengths, resulting in a total of 256 measurement points.

[0013] Furthermore, in S2, according to the inner surface rotation curve of the (k-1)th state, where k is the number of turning operations, and according to the predetermined thickness δ... k Perform equal thickness offset;

[0014] Predetermined thickness δ k Satisfy the following formula:

[0015] δ max(k-1) -ap max <δ k <δ min(k-1) -ap min ;

[0016] Where δ max(k-1) δ represents the maximum thickness before turning. min(k-1) The minimum thickness before turning, ap max For maximum damage taken, AP min This is the minimum cutting depth.

[0017] Furthermore, in step S3, the actual thickness data of the measurement points is measured to obtain the thickness δ at each point. ij ;

[0018] The positions of the measurement points are calibrated using a machine tool with a numerical control calibration, and the positional deviation is no greater than 0.3mm;

[0019] Thickness δ ij The thickness was obtained by taking the average of three consecutive measurements using an ultrasonic thickness gauge.

[0020] The minimum thickness δ of each generatrix surface at different circumferential positions is statistically analyzed. minj A total of 16 measurement points and their corresponding minimum thickness δ were obtained. minj .

[0021] Furthermore, step S4 includes the following steps:

[0022] S41. The rotation curve of the inner surface in the previous turning state is used to determine the predetermined thickness δ. k By offsetting outwards, the predetermined turning action curve of the machine tool is obtained, which represents the surface rotation curve of the Kth state;

[0023] S42. Position the generatrix surface of the current state's external surface rotation curve;

[0024] S43. According to the rotation curve of the outer surface in the previous state, the measurement point of minimum thickness is offset inward in the normal direction, and the offset thickness is the minimum thickness of the measurement point of minimum thickness on each generatrix surface.

[0025] S44. Construct a cubic interpolation spline curve for the offset measurement points to obtain the internal surface rotation curve of the current state.

[0026] Furthermore, in S5, the thickness threshold is the minimum thickness allowed by the design.

[0027] Furthermore, the maximum depth of cut is 1.5mm, and the minimum depth of cut is 0.3mm.

[0028] A second aspect of the present invention provides an electronic device including a processor and a memory communicatively connected to the processor and used to store processor-executable instructions, the processor being used to perform the method described in the first aspect above.

[0029] A third aspect of the present invention provides a server comprising at least one processor and a memory communicatively connected to the processor, the memory storing instructions executable by the at least one processor, the instructions being executed by the processor to cause the at least one processor to perform the method as described in the first aspect.

[0030] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the method described in the first aspect.

[0031] Compared with the prior art, the method for correcting static deviations of a variable curvature spherical base generatrix described in this invention has the following advantages:

[0032] The present invention discloses a method for correcting static deviations in the generatrix of a variable curvature spherical bottom during machining. This method measures and corrects the generatrix deviation after each machining operation, eliminating static deviations and reducing the generatrix deviation before and after machining the variable curvature spherical bottom. This improves the machining accuracy of the variable curvature spherical bottom with equal wall thickness, while reducing the weight of the curved box bottom while ensuring structural strength. Attached Figure Description

[0033] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0034] Figure 1 This is a schematic diagram of the turning correction method described in an embodiment of the present invention. Detailed Implementation

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0036] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] In constant-thickness turning, thickness deviations mainly arise from the discrepancy between the CNC lathe's predetermined actions and the actual internal surface shape. This deviation is divided into dynamic and static deviations. Dynamic deviations refer to the random deformation deviations of the product during the turning process, which are related to the machine's cutting state and the product's clamping state. Static deviations refer to the inherent deviations between the CNC lathe's predetermined actions and the actual internal surface shape before turning. Static deviations can be further divided into circumferential and generatric deviations.

[0038] Example 1:

[0039] like Figure 1 As shown, a method for correcting static deviations in a variable curvature spherical base generatrix during machining includes the following steps:

[0040] S1. Divide the bottom of the arc-shaped box into multiple generatric surfaces along the axial direction, and evenly set multiple measurement points around the circumference of each generatric surface;

[0041] S2. Based on the inner surface rotation curve of the previous turning state, perform equal thickness offset with a preset thickness to generate the current outer surface rotation curve, and perform turning of the outer surface using the current outer surface rotation curve.

[0042] S3. Collect the thickness at each measurement point and count the measurement points with the minimum thickness on each busbar surface;

[0043] S4. Construct the rotation curve of the current inner surface based on the minimum thickness on each generatrix surface and the position of the measurement point;

[0044] S5. Repeat S2-S4 until the minimum thickness reaches the thickness threshold and then stop turning.

[0045] The thickness threshold is the minimum thickness allowed by the design.

[0046] In S1, U i For the circumferential measurement points, i = 1, 2…16, there are a total of 16 points equally divided circumferentially, V j The generatrix is ​​a surface with j = 1, 2... 16. The generatrix is ​​divided into 16 surfaces with equal arc lengths, resulting in a total of i*j = 256 measurement points.

[0047] In S2, according to the internal surface rotation curve of the (k-1)th state, where k is the number of turning operations (when k=1, it is the theoretical internal surface rotation curve), according to the predetermined thickness δ k Perform equal thickness offset;

[0048] Before finishing, the theoretical inner surface rotation curve is offset by a predetermined thickness δ1 to form an initial outer surface rotation curve. The machine tool is then set to its predetermined actions based on this initial outer surface rotation curve to achieve the first turning of the outer surface; the predetermined thickness δ1... k The predetermined thickness δ is the thickness expected after each turning operation, which increases as k increases. k Gradually decrease.

[0049] Predetermined thickness δ k Satisfy the following formula:

[0050] δ max(k-1) -ap max <δ k <δ min(k-1) -ap min ;

[0051] Where δ max(k-1) δ represents the maximum thickness before turning. min(k-1) The minimum thickness before turning, ap max For maximum damage taken, AP min This is the minimum depth of cut. The maximum depth of cut is 1.5mm, and the minimum depth of cut is 0.3mm.

[0052] In S3, the actual thickness data of the measurement points is measured to obtain the thickness δ at each point. ij , where i = 1, 2…16, j = 1, 2…16;

[0053] The positions of the measurement points are calibrated using a machine tool with a numerical control calibration, and the positional deviation is no greater than 0.3mm;

[0054] Thickness δ ij The thickness was obtained by taking the average of three consecutive measurements using an ultrasonic thickness gauge.

[0055] The deviations on the generatrix surface vary at the circumferential positions of the 16 measurement points. Ignoring circumferential deviations, due to the rotational motion characteristics of turning, the circumferential deviations at each point on the generatrix will tend towards the same point of rotation. To determine this point of rotation, following the principle of prioritizing the minimum wall thickness during turning, the minimum thickness δ at different circumferential positions of the measurement points on each generatrix surface is statistically analyzed. minj A total of 16 measurement points and their corresponding minimum thickness δ were obtained. minj .

[0056] S4 includes the following steps:

[0057] S41. The inner surface rotation curve of the previous turning state (i.e., the inner surface rotation curve of the (k-1)th state) is subjected to a predetermined thickness δ. k By offsetting outwards, the predetermined turning action curve of the machine tool is obtained, which represents the surface rotation curve of the Kth state;

[0058] S42. According to the principle of determining the measurement points, the generatrix surfaces of the current external surface rotation curve are located to obtain 16 generatrix surfaces.

[0059] S43. According to the rotation curve of the outer surface of the previous state (i.e. the rotation curve of the outer surface of the kth state), the offset is made inward in the normal direction of the measurement point of minimum thickness, and the offset thickness is the minimum thickness of the measurement point of minimum thickness on each generatrix surface.

[0060] S44. Construct a cubic interpolation spline curve for the offset measurement points to obtain the internal surface rotation curve of the current state.

[0061] During the finishing stage, the deviation of the generatrix after each turning is measured and corrected, which can eliminate the static deviation of the generatrix, reduce the deviation of the generatrix before and after the machining of the variable curvature spherical bottom, improve the turning accuracy of the variable curvature spherical bottom with equal wall thickness, and reduce the weight of the arc-shaped box bottom while ensuring structural strength.

[0062] Example 2:

[0063] An electronic device includes a processor and a memory communicatively connected to the processor and used to store processor-executable instructions, characterized in that: the processor is used to execute the method of Embodiment 1 described above.

[0064] Example 3:

[0065] A server is characterized in that it includes at least one processor and a memory communicatively connected to the processor, the memory storing instructions executable by the at least one processor, the instructions being executed by the processor to cause the at least one processor to perform the method as described in Embodiment 1.

[0066] Example 4:

[0067] A computer-readable storage medium storing a computer program, characterized in that: when the computer program is executed by a processor, it implements the method of Embodiment 1.

[0068] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0069] In the several embodiments provided in this application, it should be understood that the disclosed methods and systems can be implemented in other ways. For example, the division of units described above is merely a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. The aforementioned units may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of the present invention according to actual needs.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for correcting static deviations in the machining of a variable curvature spherical base generatrix, characterized in that, Includes the following steps: S1. Divide the bottom of the arc-shaped box into multiple generatric surfaces along the axial direction, and evenly set multiple measurement points around the circumference of each generatric surface; S2. Based on the inner surface rotation curve of the previous turning state, perform equal thickness offset with a preset thickness to generate the current outer surface rotation curve, and perform turning of the outer surface using the current outer surface rotation curve. S3. Collect the thickness at each measurement point and count the measurement points with the minimum thickness on each busbar surface; S4. Construct the rotation curve of the current inner surface based on the minimum thickness on each generatrix surface and the position of the measurement point; S5. Repeat S2-S4 until the minimum thickness reaches the thickness threshold and then stop turning. S4 includes the following steps: S41. Determine the thickness of the rotation curve of the inner surface from the previous turning state. By offsetting outwards, the predetermined turning action curve of the machine tool is obtained, which represents the surface rotation curve of the Kth state; S42. Position the generatrix surface of the current state's external surface rotation curve; S43. According to the rotation curve of the current surface, offset inward in the normal direction of the measurement point of minimum thickness, and the offset thickness is the minimum thickness of the measurement point of minimum thickness on each generatrix surface. S44. Construct a cubic interpolation spline curve for the offset measurement points to obtain the internal surface rotation curve of the current state.

2. The method for correcting static deviations in a variable curvature spherical base generatrix during machining according to claim 1, characterized in that: In S1, There are a total of 16 circumferentially divided measurement points. The 16 busbar surfaces are divided into 16 sections with equal arc lengths, resulting in a total of 256 measurement points.

3. The method for correcting static deviations in a variable curvature spherical base generatrix during machining according to claim 1, characterized in that: In S2, the inner surface rotation curve of the (k-1)th state is used, where k is the number of turning operations, and the predetermined thickness is followed. Perform equal thickness offset; Predetermined thickness Satisfy the following formula: ； in This represents the maximum thickness before turning. This represents the minimum thickness before turning. To maximize the cut, This is the minimum cutting depth.

4. The method for correcting static deviations in a variable curvature spherical base generatrix during machining according to claim 1, characterized in that: In step S3, the actual thickness data of the measurement points is measured to obtain the thickness at each point. ; The positions of the measurement points are calibrated using a machine tool with a numerical control calibration, and the positional deviation is no greater than 0.3mm; thickness The thickness was obtained by taking the average of three consecutive measurements using an ultrasonic thickness gauge. Statistically determine the minimum thickness of each generatrix surface at different circumferential locations. A total of 16 measurement points and their corresponding minimum thicknesses were obtained. .

5. The method for correcting static deviations in a variable curvature spherical base generatrix during machining according to claim 1, characterized in that: In S5, the thickness threshold is the minimum thickness allowed by the design.

6. The method for correcting static deviations in a variable curvature spherical base generatrix during machining according to claim 3, characterized in that: The maximum depth of cut is 1.5mm, and the minimum depth of cut is 0.3mm.

7. An electronic device comprising a processor and a memory communicatively connected to the processor and used for storing processor-executable instructions, characterized in that: The processor is used to execute the method described in any one of claims 1-6.

8. A server, characterized in that: The method includes at least one processor and a memory communicatively connected to the processor, the memory storing instructions executable by the at least one processor, the instructions being executed by the processor to cause the at least one processor to perform the method as described in any one of claims 1-6.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, it implements the method described in any one of claims 1-6.

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